Using this tag you can set up your web app to have an application shortcut icon added to a device's homescreen, and have the app launch in full-screen "app mode".
nginx [engine x] is a HTTP server and mail proxy server written by Igor Sysoev.
PHP is a widely-used general-purpose scripting language that is especially suited for Web development and can be embedded into HTML.
UTF-8 (8-bit UCS/Unicode Transformation Format) is a variable-length character encoding for Unicode. It is the preferred encoding for web pages.
Chrome for Android, since version 39 supports the "theme-color" meta tag to allow websites control the background color of the tab's UI header.